1. Field of the Invention
This invention generally relates to an isolator for resisting transmission of shock and vibration forces between structures and, more particularly, to a compact isolator also operative for conducting energy such as heat and/or electricity away from at least one of the structures that emits such energy.
2. Description of Related Art
Isolators for protecting a mounted item or load structure, such as an equipment cabinet, from shock and vibration forces exerted by another structure, such as a moving vehicle, are well known and have been used in many industrial and military applications. For example, U.S. Pat. Nos. 4,190,227 and 4,783,038 disclose such isolators where such forces are damped by flexural elements constituted of single- or multiple-strand metal wire such as stainless steel wire. Such stainless steel wires flex and readily return to their original state and, hence, are very effective for isolating the load structure from shock and vibration forces.
However, such stainless steel wires are much less effective in dissipating heat from load structures that generate heat during operation. For example, the load structure may be an electric motor, a transistorized or other electronic equipment, or an electro-mechanical apparatus, any one of which generates heat during operation. The efficient performance of such load structures is strongly dependent on the effective and continuous removal of excess heat therefrom.
However, an effective shock and vibration isolator of the type described in the above-mentioned patents is not an effective heat dissipator. Stainless steel, as well as many other metals, is a relatively poor conductor of heat, when compared to such materials as copper. However, copper, being a malleable material, is not a good choice for damping shock and vibration forces, since copper wire will eventually crack when subjected to repeated flexing.
U.S. Pat. No. 4,789,023 proposed a vibration isolator that also acted as a heat sink. Heat removal was achieved by a heat pipe wherein a working fluid such as methyl alcohol was contained between outer and inner flexible, tubular enclosures and was conveyed from a condenser section to an evaporator section of the heat pipe. The fluid was converted to vapor and then re-liquefied. Such fluid flow systems were not only subject to fluid leakage, but were also not altogether satisfactory in removing waste heat. In any event, the need also sometimes exists for conducting electricity away from such load structures and, in such cases, heat pipe systems cannot conduct electricity away from the load structure.